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01-10-2014, 11:52 AM   #181
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What I am saying is that a crop sensor camera will offer you more features than a full frame sensor camera of a similar cost. And the crop camera will be smaller - if FF can be made smaller, so can crop (until designs get to small that the limiting factor is fixed thing like register distance, as we can see starting to happen with the K-01)
Magnification is also affected by resolution, if you crop a 24MP full frame shot, it still wont look like a 24MP APSC - the resolution will be different.
In regards to crop lenses being bigger and more expensive, I don't quite buy it (excuse the pun). Sure, primes might not be overly large (though, looking at the trends of Sigma 50mm and Zeiss Otus..), but zoom lenses for FF, as far as I know, are significantly heavier. The problem here is that, as mentioned, most lens manufacturers don't really make lenses optimized for crop sensors. They are often FF designs or they still project an unnecessarily large image circle. So this will change once lens brands accept crop sensor more fully. The FF and APSC markets have too much overlap atm, but this will change as companies specialize more.
Keep in mind, I am not making the argument that "crop is better than FF in every way." Its just different. And it has its uses. And saying that FF "includes the crop" is wrong. In that case, medium format includes FF. Because the difference between a FF and APSC is not only the size of the sensor. It also has different processor, size, features, ergonomics..

01-10-2014, 11:59 AM   #182
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QuoteOriginally posted by mikemike Quote
Fuji, Pentax DA ltd, and DA* 2..8 zooms show us what can be done if you design APS-C dedicated lenses. The pentax lens pricing is just a (bad) marketing choice, not a cost driven choice, DA* zooms and DA ltd lenses used to be 2/3 the price of Canikon FF lenses which covered the same focal range at the same speed. They don't cost any more to produce, they are just changing their pricing strategy. It is unfortunate for us but it doesn't mean that a similar change isn't inevitably going to happen for other brands if the margins just got too thin.

The linked article didn't reference Pentax lenses at all.
01-10-2014, 12:00 PM   #183
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QuoteOriginally posted by ElJamoquio Quote
Bigger camera? Sometimes? Usually? How big is the 6D compared to the 7D? about the same to my knowledge. The mount is the same of course.


Bigger lenses? Not usually.

Dr. Camera: APS-C lenses aren't smaller, aren't lighter, and aren't cheaper.


If pixels are a problem I'm cropping too far...
If equivalence is a big deal, then they should be about the same (except when you get really wide). A 55mm f1.4 will be about the same size as an 85mm f2. A 50-135 f2.8 on APS-C will be about the same size as a 70-200 f4 on full frame. There certainly isn't any size gain either way.
01-10-2014, 12:00 PM   #184
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QuoteOriginally posted by mikemike Quote
Fuji, Pentax DA ltd, and DA* 2..8 zooms show us what can be done if you design APS-C dedicated lenses. The pentax lens pricing is just a (bad) marketing choice, not a cost driven choice, DA* zooms and DA ltd lenses used to be 2/3 the price of Canikon FF lenses which covered the same focal range at the same speed. They don't cost any more to produce, they are just changing their pricing strategy. It is unfortunate for us but it doesn't mean that a similar change isn't inevitably going to happen for other brands if the margins just got too thin.
Fuji is mirrorless which is more of a size driver than FF vs APS-C. And the DA Limiteds are relatively slow, which also makes them smaller.

01-10-2014, 12:01 PM   #185
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QuoteOriginally posted by Na Horuk Quote
The problem here is that, as mentioned, most lens manufacturers don't really make lenses optimized for crop sensors. They are often FF designs or they still project an unnecessarily large image circle. So this will change once lens brands accept crop sensor more fully. The FF and APSC markets have too much overlap atm, but this will change as companies specialize more.
Keep in mind, I am not making the argument that "crop is better than FF in every way." Its just different. And it has its uses. And saying that FF "includes the crop" is wrong. In that case, medium format includes FF. Because the difference between a FF and APSC is not only the size of the sensor. It also has different processor, size, features, ergonomics..
I think that Canon, Nikon, and Sony will continue to produce cameras in both APS-C and FF but they will neglect APS-C only high end lenses more than they do already to shift people with money to spend to spend it on more expensive kit. This provides a niche for a company like ricoh pentax to fill.

The burden on the processor and other electronics will be driven by pixel count and color depth more than sensor size so it is quite easy for a company with FF R&D to simply sell virtually the same device with two different sensor sizes.
01-10-2014, 12:06 PM   #186
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QuoteOriginally posted by Rondec Quote
If equivalence is a big deal, then they should be about the same (except when you get really wide). A 55mm f1.4 will be about the same size as an 85mm f2. A 50-135 f2.8 on APS-C will be about the same size as a 70-200 f4 on full frame. There certainly isn't any size gain either way.
Sure, on the long end of normal the FF lenses are only slightly lighter, slightly smaller, and slightly cheaper.

On the wide end of normal the FF is even 'more better'.
01-10-2014, 12:41 PM   #187
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QuoteOriginally posted by ElJamoquio Quote
Sure, on the long end of normal the FF lenses are only slightly lighter, slightly smaller, and slightly cheaper.

On the wide end of normal the FF is even 'more better'.
I don't even know if this is true. We know how big a 40mm f2.8 XS lens is. How big would a 60mm f4 lens be on full frame? We know how big the DA 70 f2.4 is. How big would a 105mm f3.5 lens be? My feeling is that in a certain range there is some size decrease in APS-C lenses, but it is hard to know, since there are few lenses that are released in those focal lengths and apertures.
01-10-2014, 04:06 PM   #188
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It's a little more complicated than equivalent FLs for lens size, since the DA 40 (as a designated APS-C lens) is of similar size to the older M 40 pancakes (which are FF). So I consider it being more of a function of lens design for particular focal lengths. Pentax have done well to cram so much IQ and speed into something like an FA 77, which I just think is a one-of-a-kind marvel of a lens design. An equivalent APS-C version into something like a 50/1.2 is not something we can be fair to compare with.

I just wonder what successes Pentax might have in adapting the FA Ltds (particularly since they will now be produced with the HD coating) onto a FF K-mount lens, combining IQ, resolution and small size...

Lens designers have their work cut out for them. And I can truly say, well done Pentax with your FA and DA Ltds.

01-10-2014, 04:21 PM   #189
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Aside from the DOF factor, I understood (or so I thought) that f4 on FF being equal f2.8 on APS-C was simply because one can pump up the ISO by a stop on FF, and obtain the same noise as on APSC. So FF f4 ISO 800 yields "same" noise as APS-C f2.8 ISO 400, for example. This would make the f4/f2.8 a valid comparison, no?
01-10-2014, 05:09 PM   #190
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QuoteOriginally posted by bxf Quote
Aside from the DOF factor, I understood (or so I thought) that f4 on FF being equal f2.8 on APS-C was simply because one can pump up the ISO by a stop on FF, and obtain the same noise as on APSC. So FF f4 ISO 800 yields "same" noise as APS-C f2.8 ISO 400, for example. This would make the f4/f2.8 a valid comparison, no?
Noise is a factor of the sensor not of the sensor size, sensor size helps but it is not a durable advantage. You will get less noise on a K3 than you will on a 4 year old FF. If you compared K3 to some of the most recent FF though like the A7 the A7 will have less noise.

DOF and the trade-off of sharpness from shooting wide open to get the shallower DOF is the legitimate gripe. It is not a concern for a great many people, but for some people it is. ::shrug:: Whatever.
01-10-2014, 05:16 PM   #191
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QuoteOriginally posted by mikemike Quote
Noise is a factor of the sensor not of the sensor size, sensor size helps but it is not a durable advantage. You will get less noise on a K3 than you will on a 4 year old FF. If you compared K3 to some of the most recent FF though like the A7 the A7 will have less noise.

.
I think the assumption would have to be that you would comparing sensors of roughly the same tech generation/iteration, otherwise all bets regarding QE are off.
01-10-2014, 05:22 PM   #192
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QuoteOriginally posted by jsherman999 Quote
I think the assumption would have to be that you would comparing sensors of roughly the same tech generation/iteration, otherwise all bets regarding QE are off.
Correct (i.e. that was assumed in my post).
01-10-2014, 05:35 PM   #193
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QuoteOriginally posted by jsherman999 Quote
I think the assumption would have to be that you would comparing sensors of roughly the same tech generation/iteration, otherwise all bets regarding QE are off.
FF sensors have a slower generational turn over than APS-C sensors. The mid cycle APS-C sensor usually closes most of the gap leaving just DoF.
01-10-2014, 07:14 PM   #194
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QuoteOriginally posted by mikemike Quote
FF sensors have a slower generational turn over than APS-C sensors. The mid cycle APS-C sensor usually closes most of the gap leaving just DoF.
There is no current apsc sensor that closes the gap any closer than the D7000/k5 did, compared to say the D800/D600. They got a boost in pixel density, but the noise and DR gaps along the ISO range remain. What sensors were you comparing?

Last edited by jsherman999; 01-10-2014 at 07:22 PM.
01-10-2014, 08:37 PM   #195
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QuoteOriginally posted by normhead Quote
Then why does my AF stop working on my A-400 when I use it with the 2x converter in low light?
Your 2x converter enlarges the image circle, thus "throwing away" two stops worth of light. In other words, your 2x converter reduces the exposure.

The AF module has less light to work with but more importantly, the effective aperture for your A-400 + 2xTC combination is f/11, which is too small for the AF system. The AF system starts to become blind around "f/8" so it does not receive any useful light anymore at f/11. This is a consequence of how phase-based AF systems work and is analogous to the "blacking out" of split-prism focusing aids.

QuoteOriginally posted by normhead Quote
Why doesn't that separate AF unit continue to function, when shooting with my 18-135 I can shoot into almost total blackness. This is not a theoretical argument for me. I base what I am saying on practical observation.
As I wrote above, it isn't the low light levels that causes your A-400 + 2xTC combination to stop working but a "blacking out" effect for the AF module. So the theory completely bears out your practical observations.

QuoteOriginally posted by normhead Quote
..., ƒ 2.8 collects the same amount of light, in terms of density of distribution along the film plane.
Correct.

QuoteOriginally posted by normhead Quote
If the AF sensor are the same size then they receive the same amount of light, ...
But the AF optics can be bigger in an FF camera. The image circle is bigger, i.e., there is more light to collect, so the AF optics may as well make use of it.

In other words, an AF module for an FF camera is not intrinsically disadvantaged by equivalent lenses, i.e., it can work just as well with an f/4 lens as an APS-C AF module can work with an f/2.8 lens.

QuoteOriginally posted by normhead Quote
...and even if they aren't. You have to ask yourself if this is true, how does the K-5 and K-3 achieve such amazing low light focus. You guys spin this stuff and throw it out there, but it makes me wonder if you actually use real cameras, or if you just read about them.
The K-5 does not achieve amazing low-light focus. It is prone to providing false focus confirmation and has issues with front-focus in the presence of lower light temperatures.

The K-5 II and K-3 achieve excellent low-light focus because they have the corresponding AF optics (including a diffraction lens design).

Enlarge the same module and put it into an FF camera and you get the same amazing low-light AF for equivalent apertures (e.g., f/4 vs f/2.8) and even better for the same apertures (e.g., f/2.8 vs f/2.8).

QuoteOriginally posted by normhead Quote
A 2.8 lens collects exactly the same amount of light be it on an FF or APS-c. But on APS-c when using an FF lens, half the light doesn't reach the sensor, because the sensor is smaller.
So of what use is the light the f/2.8 lens collected that is cropped out by the APS-C sensor?
That light is lost so for all intents and purposes it makes sense to state that an f/2.8 lens collects less light on an APS-C sensor than it does on an FF sensor.

This is particularly true if the f/2.8 lens is "optimised" for APS-C and only projects an APS-C-sized image circle. Such a lens clearly puts out less light than an f/2.8 lens for FF.

QuoteOriginally posted by normhead Quote
And the number of photons hitting any part of the sensor in a 1mm x 1mm area is the same on any system.
Correct.

However, the larger sensor has more of these "1mm x 1mm areas".

So for the same exposure (say we are using f/2.8 on an APS-C camera and an FF camera), the larger sensor collects more photons.

Both sensors collect the same amount of photons in the area covered by the smaller sensor, but there is additional area surrounding the latter in the larger sensor that collects additional photons.

If you keep the same exposure then these additional photons increase image quality (more than 1 stop noise advantage for APS-C vs FF; this is certainly visible).

Alternatively, you could reduce the number of photons collected by the larger sensor by reducing the exposure.

If the number of photons becomes the same then the image quality is the same. If you reduce exposure by stopping down, you also get the same DOF.

Do you now see that a larger sensor can afford to receive less exposure because it can compensate with its larger light-sensitive area?

QuoteOriginally posted by normhead Quote
From the old days when we used light meters, everyone of us knows. You use the same light meter for 35mm or 8x10 film and every camera in between. For exposure, if your light meter says ƒ8 at 100th of second, it's the same for every camera of every size.
Sure, that's because light meters are meant to give you the same exposure.

However, note that "same exposure" means "better image quality" the larger the format (see above). The idea of maintaining the same exposure independently of the format implicitly contains the idea that you want to be able to print larger with the larger format. If you maintain the same exposure with a format that is twice as large as another, you can now print twice as large and the print will look just as good even on close inspection.

Yet, if you are only concerned about one particular print size, or want to do a fair comparison then you can afford to reduce the exposure on the larger format. The resulting print will look just as good as the one from the smaller format (given the same print size). Again, that's because the same number of photons have been used.

QuoteOriginally posted by normhead Quote
There is absolutely no way, ƒ2.8 on one system is equivalent to ƒ4 on another.
The law of physics say otherwise.

Please read the sources I provided (one of them written by a physicist) and point out the flaws in the arguments. There aren't any.

QuoteOriginally posted by normhead Quote
Ansel Adams was part of the ƒ64 club, so, his preferred shooting aperture was ƒ64, hardly the guy to bring up if arguing for the narrow DoF argument. so if you're going to talk about equivalency and the need for less DoF, I can hear the man laughing.
Please read more carefully.

I wrote
"Do you think Ansel Adams dragged up big and heavy equipment up mountains because he was after a "shallow DOF" aesthetic? He certainly wasn't."
In other words, I said
  • Ansel Adams was not interested in shallow DOF.
  • He nevertheless used a large format camera.
  • There are reasons to use large formats other than aiming at a "shallow DOF aesthetic".

QuoteOriginally posted by normhead Quote
Lenses could be pretty bad because the image wasn't magnified much and you tried to shoot at ƒ64, because with that size negative, diffraction isn't really an issue very often.
You just listed two advantages for larger formats that also apply to the FF vs APS-C comparison.

If you turn the argument around, it says that APS-C lenses need to be better than FF lenses in order to achieve the same image quality. That's why starting with a certain image quality, FF lenses become the cheaper option because they don't have to be manufactured with the same precision as APS-C lenses. Hence, the "FF lenses are more expensive" argument fails at a certain point (and isn't true most of the time anyhow, if you compare equivalent lenses).

Last edited by Class A; 01-10-2014 at 08:50 PM.
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